Big Guns of Camp Carroll

1997 by Peter Brush

(Note: This article appeared in Vietnam magazine, Vol. 10, No. 2, August 1997, pp. 26-32.)

Summary: U.S. strategy for the defense of the DMZ called for interlocking bands of artillery fire, and the firebase at Camp Carroll was the linchpin.

American military commanders are taught to use generous volumes of firepower instead of manpower to accomplish their military objectives and to minimize their casualties. Thus the ideal tactical environment for the United States was to dot the landscape of South Vietnam with innumerable artillery firebases capable of achieving interlocking fields of fire. Fully aware of the tactical value of artillery, the American military would expend more than seven million tons of it on targets in Vietnam.

In early 1966, the North Vietnamese Army (NVA) began massing forces in the northern provinces of South Vietnam, and the Marines were ordered north to face this threat. The area in the eastern Demilitarized Zone (DMZ) had been heavily infiltrated by the enemy. The 324B NVA Division had crossed the DMZ and was quite willing to tangle with the Marines. Reconnaissance patrols were unable to stay in the field for more than a few hours -- and many for only a few minutes -- before it was necessary to extract them under heavy enemy fire. A new phase of the war in Vietnam was about to begin.

Operation Hastings, the largest coordinated offensive operation of the war up to that time, was launched on July 15, 1966. Five Marine infantry battalions were inserted into landing zones and given the mission of establishing blocking positions along enemy trails and killing enemy soldiers. A reinforced battalion of Marine artillery accompanied this task force. A headquarters was established at Dong Ha, located about 12 miles from the DMZ and 12 miles from the coast of Vietnam. From Dong Ha, the Marines pushed along National Route 9, establishing firebases at Cam Lo and at a 700-foot mountain known as "the Rockpile."

The ground between Dong Ha and Cam Lo is level. As you move westward, the terrain becomes more rugged and is composed of a series of ridges and steep hills rising to elevations of over 1,600 feet. During Operation Hastings, the Marines adopted the tactic of launching deep reconnaissance patrols into these hilly areas. On July 28, one of the patrols operating near the Rockpile noted the presence of approximately 200 NVA troops. Artillery fire was called in on the enemy force, resulting in 50 killed North Vietnamese. The marriage of reconnaissance and artillery support used in that patrol was termed "Sting Ray," and Sting Ray patrols came to be considered one of the major innovations of the war.

Employing supporting arms that included artillery firing 34,500 rounds, Marine tactical aircraft flying 1,667 sorties, helicopters carrying out nearly 10,000 sorties, and Boeing B-52 strategic bombers striking targets in the DMZ for the first time, the Marines were able to destroy more than 700 enemy troops by the time Operation Hastings ended in August 1966. Marine casualties for the operation totaled 126 killed and 448 wounded. Operation Prairie immediately commenced in the same tactical area. From the womb of Prairie, Camp J.J. Carroll was born.

One of the key terrain features in the otherwise open area along the DMZ was the Rockpile. A reconnaissance patrol rappelled from a helicopter and set up an observation post on the mountain's summit, allowing many Sting Ray patrols to be controlled from that site. According to U.S. intelligence reports, the 324B NVA Division was solidly entrenched to the north of the Rockpile, protecting its infiltration routes into South Vietnam. Large numbers of enemy soldiers were detected along the Nui Cay Tre ridge to the north, from which they bombarded the Marines on the mountain. It was decided that the NVA must be swept from their position to protect the Marines on the Rockpile from further mortar attacks. The effort resulted in the longest action of Operation Prairie, lasting from September 22 through October 5, 1966.

Two hills dominated the ridgeline. As the Marines attacked Hill 400, the nearest position, it became clear that they were entering the enemy's main line of resistance. The fighting was intense. Once Hill 400 was secured, the Marines pushed on to their final goal, Hill 484. After an initial frontal attack was thrown back by the North Vietnamese, the Marines attacked again -- this time attempting to envelop the enemy from the left. The Marines were once again thrown back. Air and artillery were then called in to soften up the enemy positions.

On the evening of October 4, the commanding officer of Company M, 3rd Battalion, 4th Marines, brought up tanks to assist in the final assault on Hill 484. The commander of Company K, Captain James J. Carroll, had assisted the tank gunners in practice firing against likely targets to ensure that the guns were properly sighted. Captain Carroll, who had arrived in Vietnam a month before the battle, had described the fighting for Hill 400 as "the high point of my career." That evening, the tanks Carroll had helped to sight were replaced with other Marine tanks. These new tanks, when called to action on Hill 484, proved to be improperly sighted.

At 1000 hours on October 5, Company M advanced toward the NVA atop Hill 484. Believing that artillery fire would be ineffectual due to the steepness of the slope, the company commander ordered direct tank fire against enemy positions on Hill 484. Five rounds were ordered. Two came at the target; both missed the enemy troops and instead hit Marines positioned on Hill 400. Thirteen casualties resulted from the friendly fire, including Carroll, who was killed. By early afternoon the NVA had been pushed off Hill 484. For a time, the Rockpile was safe from NVA mortar bombardment.

Another Marine artillery position had been established on a nearby ridge, called "Artillery Plateau." This position became the command post (CP) of the 3rd Marine Regiment. When the commander of the 3rd Marines, Colonel Edward E. Hammerbeck, established his CP in the north, Artillery Plateau had not yet been named Camp Carroll. It was not until November 10, 1966 -- the birthday of the Marine Corps -- that the plateau was officially dedicated as the bases camp of the 3rd Marines and given the name Camp Carroll.

Operation Prairie lasted until the end of January 1967. Marine casualties were more than 1,384 killed and wounded. Prairie was followed by Operations Prairie II, III, and IV. Nine artillery firebases were constructed along the DMZ, with Camp Carroll -- equipped with 16 guns -- in the center. The 80-gun artillery fan was completed with the addition of U.S. Army 175mm long-range guns. The Marines could direct artillery into almost any grid coordinate from the South China Sea to Laos, as well as into North Vietnam. Airfields at Dong Ha and Khe Sanh were constructed, as well as a sizable port facility at the mouth of the Cua Viet River. Large Marine forces would remain in the area for three more years.

On July 5, 1967, the Marine base at Con Thien came under NVA mortar and artillery attack. An air observer noticed large numbers of enemy troops of the 90th NVA Regiment advancing behind the barrage. The Marines called in artillery and airstrikes, and the artillerymen at Camp Carroll and the other bases responded, repelling the NVA attack. By the morning of July 8, the fighting had fallen off sufficiently for the Marines to attempt a body count of enemy soldiers, which eventually rose to more than 800. The scene was grisly almost beyond description. Bodies covered the battleground, some half buried by the explosions, others in pieces, all surrounded by broken equipment and munitions. The Marines tried counting enemy canteens to get a realistic number of enemy killed. An accurate count proved impossible because the Marines could not enter the area north of the Ben Hai River, which separates North and South Vietnam. It was publicly stated U.S. policy that American forces would not enter North Vietnam. But even with no exact body count, it was clear that the U.S. artillery had done its job well.

Unlike better known places in I Corps such as Khe Sanh, Con Thien or Hue, Camp Carroll was never the focus of NVA wrath until the very end of the war. Rocket attacks were launched at Camp Carroll on March 6 and March 12, 1967, but no ground attacks followed. Artillery attacks on Carroll were secondary to larger tactical goals. One such attack occurred in April 1967, when the NVA made plans to overrun the combat base at Khe Sanh. The long-range guns at Camp Carroll could easily augment the defenses of Khe Sanh, which was 13 miles away. The NVA's plan to isolate Khe Sanh included attacking Camp Carroll and other bases with artillery and rockets in order to create a diversion and minimize the Marines' ability to provide supporting fires. The NVA fired roughly 1,200 rockets, mortar, and artillery rounds in these attacks.

The North Vietnamese matched the buildup of Marine forces along the DMZ. In the spring of 1967, the NVA introduced rockets, mortars, and heavy artillery into the zone to support their ground actions. The most powerful enemy guns were capable of hitting targets at ranges greater than ten miles, putting most firebases, including Camp Carroll, within range. According to American intelligence reports on the enemy order of battle, the NVA had 130 artillery pieces in the area north of the Ben Hai River at the time. To counter that threat, the Marines increased their own artillery deployment to 180 tubes.

The biggest problem for the Marines in the region was determining the precise location of the Communist artillery. Ground observation was limited by political and military restrictions against operations in the DMZ. Aerial observation was hindered by NVA missile and anti-aircraft fire. Since the Marines were usually firing from fixed permanent positions located on prominent terrain features, the NVA had a clear choice of targets for their gun crews. The Americans repeatedly blasted suspected NVA gun positions with artillery, airstrikes, and naval gunfire, but despite those measures, the Communists were still able to inflict significant casualties.

In May, 1967, the Marines became concerned with the NVA's use of the southern half of the DMZ for rocket-launching and artillery sites. Altogether 12,000 Vietnamese civilians were removed from the operational area by the South Vietnamese National Police. After the civilians had been moved out, the entire area was considered a free-fire zone. The Americans then launched several operations in the region between the Ben Hai River and Route 9 intended to destroy all enemy units, installations, and supplies.

The Soviet tactic -- which the North Vietnamese followed -- was to position their heavy artillery pieces just beyond the range of U.S. 105mm and 155mm artillery, the most common guns in the U.S. artillery arsenal (with 10,500 and 14,800 meter ranges, respectively). The Soviet 152mm guns had a range of 14,955 meters, while the 130mm field piece could shoot 31,000 meters (about 19 miles). That meant that the NVA could fire on most American artillery bases with little threat from effective return fire.

From a tactical perspective, therefore, the U.S. Army 175mm self-propelled gun was the most important weapon at Camp Carroll. The 175mm guns put Camp Carroll on the map, particularly the tactical maps of the North Vietnamese forward observers. The most powerful American field artillery tube, the 175mm could fire a 150-pound projectile 32,690 meters and effectively return fire on any enemy gun that could hit it. These guns were mounted on a tracked chassis and powered by a turbocharged diesel engine. The top speed of this 30-ton monster was 35 mph, and it could fire at a rate of about one projectile every two minutes. The 175mm guns' 34 foot-long barrels, made at the Watervliet Arsenal in Troy, N.Y., would burn out after firing 300 rounds. Used barrels were half-buried in the mud, forming effective speed bumps to ensure that base traffic did not exceed the 5 mph speed limit at Camp Carroll.

Further west on Route 9, past Camp Carroll and the Rockpile, is Khe Sanh, which the Marines were ordered to reinforce in the summer of 1967. At Khe Sanh, the NVA supply lines were short while American supply lines were long. The NVA could bombard the base with long-range artillery hidden in Laos, where U.S. forces were not allowed to strike back. The primary American supply route to Khe Sanh was a truck convoy from the Marine base at Dong Ha. In August, the Marines dispatched a convoy of 85 trucks with several 175mm cannons to Khe Sanh. After the NVA ambushed the convoy along Route 9, west of Camp Carroll, the Marines decided to leave the 175mm guns at Camp Carroll while the convoy continued on to Khe Sanh. In early August, the convoys to Khe Sanh ended. That stretch of Route 9 was closed by the NVA and would remain closed for the next nine months. During the fighting around Khe Sanh that followed, Marine artillery, including the guns at Camp Carroll, would fire more than 150,000 rounds against the North Vietnamese.

In late 1966, Secretary of Defense Robert McNamara had approved plans for the construction of an anti-infiltration barrier below the DMZ. Senior Marine and Navy commanders opposed the concept, believing it would be a waste of limited resources and would result in unnecessary U.S. casualties, but General William Westmoreland, commander of U.S. forces in Vietnam, ordered the Marines to implement the plan. The "McNamara Line" was to be a linear barrier 30 kilometers long, extending from the South China Sea to a point north of the Rockpile. It would consist of barbed wire, minefields, sensors, watchtowers, and a series of strongpoints. Artillery positions along Route 9 would provide fire support for the barrier. Camp Carroll was to be one of the artillery bases.

The Marines were concerned that construction of the barrier would tie up all their resources and fix them in place, limiting their ability to conduct mobile operations. Construction efforts were hampered by the monsoon weather and fierce NVA resistance. The Marines felt that they were unable to adequately defend themselves from enemy attacks and maintain construction schedules at the same time. They estimated that in constructing the barrier, there would be 672 Americans killed, 112 South Vietnamese killed, 3,788 Americans wounded and 642 South Vietnamese wounded. Equipment lost to enemy action during construction would total $1,622,348.

The Marine 11th Engineer Battalion was given the job of constructing the barrier. Part of the task consisted of constructing roads to supply the artillery bases. The monsoon rains of 1967 turned the existing roads into impassable quagmires. One road construction job between Cam Lo and Con Thien required the engineers to use dump trucks to haul crushed rock from a quarry near Camp Carroll. During the entire trip -- more than 15 miles, the trucks were within the range of NVA artillery emplaced in the DMZ. Eventually the barrier project was abandoned.

After the Tet and post-Tet Offensives of 1968, the Communists re-evaluated their military position in northern I Corps. The North Vietnamese shifted their tactics away from an attempt to win an immediate victory to a policy of prolonging the conflict while reducing their own casualties. Communist strength in the area fell from 94 battalions in mid-1968 to 29 battalions by year's end. By then, artillery fire from within the DMZ onto U.S. positions had all but ceased.

Camp Carroll diminished in significance after the 1968 offensives. The 3rd Marine Division began adopting U.S. Army tactics, relying on highly mobile postures rather than remaining in their fixed positions as sitting targets. Marine units that had been positioned along the DMZ began receiving orders to leave the country. The withdrawals were a partial implementation of President Nixon's policy of Vietnamization -- turning the war against the Communist insurgents over to the South Vietnamese. Remaining Marine units extended their lines to plug the gaps left by departing units. As the Marines pulled out of the artillery bases in the western sector, the South Vietnamese rejected the offer to occupy the vacated Marine bases.

By October 1968, the Marines noted that enemy attacks in their area of responsibility had fallen by more than 50 percent compared to preceding months. Vandergrift Combat Base, built during the siege at Khe Sanh located west of Camp Carroll on Route 9, was dismantled by Army of the Republic of Vietnam (ARVN) forces. Salvaged materials from Vandergrift were used to construct a new ARVN combat base at Camp Carroll. In October, the Marine base at the Rockpile was closed, leaving Camp Carroll as the westernmost major installation along Route 9. As the Marines left the DMZ area, they passed control over to units of the U.S. Army and the ARVN. After a time, no U.S. forces were located in the western portion of northern I Corps; the North Vietnamese slowly began to rebuild their base areas along the Vietnam-Laos border.

Attempting to duplicate the success of the 1970 invasion of Cambodia, President Nixon ordered an invasion of Laos early in 1971 to cut NVA supply lines along the Ho Chi Minh Trail. In January, the base at Khe Sanh, which had been abandoned in 1968, was reopened to provide a logistics center for the invasion. Marine helicopters were used to move supplies and artillery from Camp Carroll to Khe Sanh. By that time, the Marines had received 175mm guns of their own. The single Marine artillery battalion in northern I Corps was the 175mm gun battery located at Camp Carroll. In March 1970, the Marine unit that had been stationed at Camp Carroll left Vietnam. The Marine Corps was finished with Camp Carroll. Enemy activity in the region was at a standstill. The fire support bases built by the Americans were manned at minimum strength by the South Vietnamese.

On June 13, 1971, Secretary of Defense Melvin Laird announced that 90 percent of the combat responsibility for the war in Vietnam had been assumed by the ARVN armed forces. Vietnamization was proceeding on schedule. U.S. Marine Corps presence in I Corps had fallen from 80,000 men to 250. By the end of 1971, enemy activity along the DMZ was at its lowest level since the days of Operation Hastings in 1966. The 3rd ARVN Division, a new unit of 11,203 men, was assigned to duty along the DMZ. The troops were only marginally trained, with little experience fighting in the area. The center of ARVN defenses along the DMZ was Camp Carroll, where an infantry regiment and five artillery battalions were located, making it the largest ARVN base in I Corps.

On March 30, 1972, the NVA launched its largest offensive so far in the Vietnam War. Nearly 30,000 soldiers, with tanks, artillery and missiles, crossed the DMZ. Hundreds of rockets and artillery shells slammed into Camp Carroll and every other ARVN installation in the area. Carroll received more than 200 rounds of Soviet 130mm fire in the first hour of the attack. The U.S. Army adviser to the ARVN at Camp Carroll noted that the enemy incoming rounds caused tremendous morale problems because the South Vietnamese were not used to being on the receiving end of accurate artillery fire. Three regiments of NVA artillery continued to pound the ARVN firebases, firing more than 11,000 rounds in the first day of the Eastertide Offensive. As ARVN gun crews sought shelter, their counterbattery fire became less and less effective, and the NVA offensive continued to intensify. The only guns that could reach the NVA 130mm artillery were the 175mm guns at Camp Carroll and Dong Ha. Whenever the ARVN 175mm guns fired, the NVA countered with a heavier barrage. The ARVN artillerymen abandoned their positions.

With the fall of ARVN bases in the west, a new defensive line was established with Carroll at the forefront. Artillery attacks on Camp Carroll intensified as the NVA sought to eliminate the biggest danger to their attacking infantry. NVA artillery observers watched every helicopter attempting to resupply Camp Carroll and fired at the landing zone when the helicopters were releasing their loads. By April 2, eight ARVN firebases had fallen, and the NVA began ground attacks on Camp Carroll.

The commander of Camp Carroll was Lieutenant Colonel Pham Van Dinh, who had become a national hero for his actions during the Tet Offensive of 1968. Dinh had assisted in raising the South Vietnamese flag over the Citadel in Hue when it was retaken from the NVA. As the situation worsened near Camp Carroll, the ARVN division commander told Dinh to act "as he thought proper." At 1430 hours on April 2, 1972, Dinh communicated to the NVA via radio that Camp Carroll would surrender, and a white flag was raised over the main gate of the camp. Colonel Gerald Turley, the senior U.S. advisor to the ARVN in I Corps during the 1972 invasion, considers the surrender of Camp Carroll to have been one of the most emotional war scenes ever recorded in Vietnamese history. The American advisers were stunned by the camp's surrender, which left a catastrophic void in the shrinking ARVN defensive line. The South Vietnamese government ordered B-52 strikes against Camp Carroll in an effort to deny its use to the North Vietnamese, but before they could strike the NVA had moved out the self-propelled guns that had been positioned at the camp, which they later used against the ARVN.

Less than 24 hours after his surrender, LtCol. Dinh made a broadcast over Radio Hanoi stating that he had been well-treated by the Communists and urging all ARVN soldiers to refuse to fight. Today, Dinh is a high-ranking official of the Communist government in Hue.

Twenty-five years after the fall of Camp Carroll, little is left to indicate that there was a major military installation there. B-52s cracked open the bunkers like walnuts. Local people finished the destruction by extracting the reinforcing bars to sell as scrap steel. Chunks of concrete were recycled into other construction projects. The perimeter trenches are overgrown. Some military detritus still liters the ground. Now the area belongs to Xi Nghiep Ho Tiev Lam, the state pepper enterprise. Pepper plants grow up jackfruit trees, and there are rubber plantations nearby.

A Marine Corps veteran of the Vietnam War, Peter Brush was stationed at Camp Carroll in 1967 and 1968 and revisited the area in 1993. Suggestions for further reading: The Easter Offensive, by G. H. Turley (Warner Books); and The U.S. Marines in Vietnam, 1966, by Jack Shulimson (Headquarters, U.S. Marine Corps.

Back to Essays by Peter Brush on Grover Furr's Vietnam War Page. | | HTML'd 18 Apr 2001